Prem Tiwari

This plugin should work with any WooCommerce version installation, since it hooks up to the core functionality of WooCommerce. The search functionality in woocommerce admin order listing page doesn’t search by sku by default. 
This simple plugin will extends the search functionality in woocommerce admin order listing page. Just install and activate from admin panel – no any settings required.
<a href="http://www.freewebmentor.com/2016/01/woocommerce-search-order-by-sku.html" rel="nofollow ugc">See the demo here</a>
Tested with Woocommerce 2.0.18, 2.2.4 and 2.2.10

Search order by SKU

This plugin will provide the extra search functionality to your product by SKU number. This simple plugin adds this functionality to both the admin si …

mattsgarage

The search functionality in woocommerce doesn’t search by sku by default.
This simple plugin adds this functionality search facility of your site, in both the public site and admin panel
Just install and activate – no config required.
Tested with Woocommerce 1.5.6, 2.0.7, 2.0.18, 2.2.4, 2.2.10, 3.4.4, 4.0.1 and 4.2.0
See the <a href="http://www.mattyl.co.uk/2012/12/11/woocommerce-plugin-to-search-products-by-sku/" title="accompanying blog post" rel="nofollow ugc">Accompanying blog post</a> for more information.

Search by SKU for Woocommerce

Extend the search functionality of woocommerce to include searching of sku

Search order by SKU vs Search by SKU for Woocommerce